Earwigs are common insects found globally, recognized by the distinctive pair of pincer-like appendages extending from their abdomen. They undergo incomplete metamorphosis, meaning their young, called nymphs, hatch resembling a smaller version of the adult. The appearance of these nymphs, often mistaken for other garden insects, changes as they grow through a series of molts.
Key Features of Earwig Nymphs
Newly hatched earwig nymphs, or first instars, are tiny, typically measuring only about 2 to 3 millimeters in length. Their size is comparable to a small ant or a young aphid, making them difficult to spot. Immediately after emerging from the egg, their coloration is pale, appearing translucent or milky white. This pale exterior is due to their soft, unhardened exoskeleton.
The nymph’s body structure is elongated and segmented, maintaining the general shape of an adult earwig. The light color quickly darkens as the exoskeleton hardens, transitioning to a light gray or tan shade within a few hours or days. Their antennae are long relative to their small size, used for sensing their environment. This helps distinguish them from the larval stages of other insects.
Distinguishing Nymphs from Adult Earwigs
The features that differentiate a nymph from an adult are size, wing development, and the structure of the cerci, or pincer-like appendages. Earwigs must shed their outer skin four to six times in a process called molting, with each stage known as an instar, before reaching full adult size. Nymphs are considerably smaller than the quarter- to one-inch long adult earwigs.
Nymphs are completely wingless throughout their developmental stages, whereas adults of many common species possess short, leathery forewings that cover membranous hindwings. The cerci on a nymph are undeveloped, appearing as small, straight, and thread-like filaments. In contrast, adult earwigs have larger, more robust cerci that are often curved in males and straighter in females, a feature known as sexual dimorphism. The fully formed cerci of the adult are used for defense, prey capture, and courtship rituals, functions the young nymphs cannot yet perform.
Common Nymph Habitats and Behavior
Baby earwigs are most frequently discovered in dark, consistently moist environments, as they are highly susceptible to dehydration. These locations include underneath rocks, within layers of leaf litter, in mulch, and under tree bark. The female earwig selects a secluded burrow or cell in the soil to lay her eggs, making these concealed spaces the initial home for the newly hatched young.
A unique behavior among earwigs, uncommon in most non-social insects, is maternal care. The mother earwig guards her clutch of eggs and continues to protect the young nymphs after they hatch. When a nest is disturbed, a cluster of young nymphs is often found close to the adult female. The nymphs remain near their mother until they reach the second or third instar before dispersing to forage independently.